Continuous processing for biologics manufacturing has numerous advantages over traditional fed batch, but many challenges remain. Improvements in media have achieved higher viable cell densities (VCD) and, in turn, higher titers in perfusion processes. However, these elevated cell densities can become unsustainable, resulting in viability loss and shortening of the perfusion run. A wasteful cell bleed can be utilized to maintain a sustainable VCD and preserve viability, but it decreases the product yield per run as the product within the cell bleed is not harvested. In order to decrease cell bleed, cell proliferation must be inhibited once the desired viable cell density is reached in the production phase. This study demonstrates cell growth arrest of perfusion Chinese hamster ovary (CHO) cell cultures testing several generally regarded as safe (GRAS) compounds that are routinely used in many chemically defined media. High density CHO cultures were grown in small scale high-throughput models with daily medium exchanges to mimic perfusion. Several of the compounds tested were found to inhibit replication in a dose-dependent manner, allowing users to determine the extent to which proliferation will be repressed. Critically, these molecules can inhibit proliferation without negatively affecting cell specific productivity (qP) or viability. Further analysis using flow cytometry showed cells arrested in the G0/G1 phase of the cell cycle, generally regarded as the most productive state. By controlling cell growth and thus minimizing cell bleed, the product recovered per perfusion run is greatly increased, generating a more efficient method for operating perfusion processes.

Strategies to modulate CHO cell growth and reduce cell bleed product loss in high density perfusion cultures using classic cell culture medium nutrients

253rd National Meeting (2017)

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